The present invention pertains to an apparatus for spot welding or linear welding. More particularly, the present invention pertains to a lightweight spot welding and/or linear welding apparatus which protects against electric shock and features a transformer formed of one or more toroidal cores, primary windings wound axially about the core or cores, and a single-turn secondary winding comprising at least two arm sections which are electrically connected by a wound elements.
In conventional welding apparatus, emphasis has been placed in developing particular features to make such an apparatus better suited for various applications. For example, U.S. Pat. No. 3,211,885 states that the commercial applicability of a portable welding tool depends upon the ease with which the tool may be used, and goes on to disclose a welding system including a capacitor discharge circuit for accommodating different sizes or gauges of material or wire to be welded. U.S. Pat. No. 2,269,726 relates to a manual welder which is described as light in weight. U.S. Pat. No. 4,496,821 states that, due to their mass, conventional spot welder transformers are not well suited for use with, for example, a robot arm, and goes on to disclose a lightweight transformer adapted for use with a welding gun mounted at the end of a robot arm. U.S. Pat. No. 2,491,169 is directed to a relatively lightweight welding means which incorporates a transformer containing little or no iron, but which permits a relatively large throat.